Ink jet printer and its head device

Abstract

An ink jet printer and a head device of the ink jet printer wherein there are provided a plurality of printer heads each having N nozzles that are arrayed in the sub-scanning direction at an interval of K pixels for a pre-set resolution, where K/N is an irreducible fraction. The printer heads are each arranged so that the nozzles are disposed along the main scanning direction depending on the colors of the emitted ink. The printer heads are also arranged with a shift of L pixels relative to one another in the sub-scanning direction. During one scanning in the main scanning direction of the printer head, only one color ink is recorded (deposited) on the same line of a recordable member to prevent the second color ink from being recorded before drying of the first color ink to achieve printing of a picture of high picture quality. By arranging the printer heads with a step-like shift of L pixels so that L<N, the head device may be rendered smaller in size than the conventional head device. In particular, if a large number of nozzles are provided for high-speed printing, this effect becomes more outstanding.

I claim: 
     
       1. An ink jet printer comprising: a head device that can be moved relative to a recording member in a main scanning direction and in a sub-scanning direction perpendicular to the main scanning direction to print at least one recorded line on the recording member, said head device including a plurality of printer heads each having N nozzles that emit colored ink, said N nozzles being arrayed in the sub-scanning direction at an interval of K pixels for a pre-set resolution, where K/N is an irreducible fraction;   signal processing means for re-arraying picture data in said sub-scanning direction and outputting the re-arrayed data; and   color correction means for reading a maximum number of recording sequences that can be assumed by the re-arrayed data outputted by said signal processing means and printed by said head device for each recorded line on the recording member and correcting colors of the picture data based on read results,   said printer heads being arranged so that said nozzles are disposed along said main scanning direction based on the colors of ink emitted from said nozzles, said printer heads also being shifted L pixels relative to one another in said sub-scanning direction.   
     
     
       2. The ink jet printer as claimed in claim 1, wherein said signal processing means includes under-color removing means for extracting black color component data from complementary color data on which the picture data is based. 
     
     
       3. The ink jet printer as claimed in claim 1, wherein said color correction processing means has a memory that stores an optimum color correction processing data corresponding to an ink emission sequence of each of said plurality of printer heads. 
     
     
       4. The ink jet printer as claimed in claim 1 wherein said plurality of printer heads are arranged with a step-like shift of L pixels relative to one another. 
     
     
       5. The ink jet printer as claimed in claim 1 wherein said plurality of printer heads are shifted L pixels relative to one another and wherein L<N.